The prize and the price: environmental fears

The biggest prize is the oil, gas and other minerals. These have been trapped under layers of permanent ice until now but, because of global warming, the deposits are becoming more accessible and surrounding countries are readying for a battle over rights. The amounts are relatively small compared with the present production of fossil fuels, but could be important locally. Finding copious oil near Greenland could allow it become more independent of Denmark. Oil reserves near Alaska could reduce the US need for foreign oil.

The retreating ice will also open up shipping routes, including the north-west passage that would link the Atlantic and Pacific oceans for year-round commercial shipping. In the 19th century, sailors dreamed of such a route as it would have halved the time it takes to get between Japan and northern Europe.

Warming seas will also mean greater numbers of fish can be caught for food, and greater opportunities for tourism.

Anything in international waters is regulated by the UN law of the sea convention, which has been ratified by all the Arctic countries except the US (though President Barack Obama is likely to support the treaty). The treaty allows countries to extend their control and exploitation of the seabed up to 350 nautical miles from their borders. This can lead to disputes over how different countries define their borders, particularly when the continental slope can extend for many miles underwater.

What are the disputes?

There are several. Russia began the land grab in 2001 and even planted a flat under the north pole in 2007, but none of these acts have much formal acceptance. One disagreement concerns the Lomonosov ridge, a 1,200-mile underwater mountain range connecting Siberia to Ellesmere Island in Canada. Russia claims it is part of the Asian continental shelf, but Canada says it is part of the North American one. UN scientists will make the final decision, but Russia, Denmark, Norway, Canada and the US are all engaged in research projects to make sure their case is heard.

In recent months, Russia has become increasingly twitchy: a Kremlin security strategy views the Barents sea shelf and other Arctic regions as potential battlegrounds in future clashes over energy reserves.

What are the environmental consequences?

If all the oil and gas that is thought to be in the Arctic is drilled out, it will inevitably mean an acceleration in the amount of carbon dioxide in the atmosphere. Opening up new fisheries, unless done sustainably, could wipe out marine and other ecosystems around the pole. This would be exacerbated by the effects of increased merchant and tourist shipping. Whatever happens to the Arctic in the coming decades, it is unlikely to be beneficial.